Inducible Expression of both ermB and ermT Conferred High Macrolide Resistance in Streptococcus gallolyticus subsp. pasteurianus Isolates in China.
Inducible Expression of both ermB and ermT Conferred High Macrolide Resistance in Streptococcus gallolyticus subsp. pasteurianus Isolates in China.
复制标题
ermB 和 ermT 的诱导表达赋予溶没食子链球菌亚种高大环内酯耐药性。
DOI：
10.3390/ijms17101599
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发表时间：
2016-09-22
影响因子：
5.6
通讯作者：
Liu C
中科院分区：
文献类型：
--
作者：
Li M;Cai C;Chen J;Cheng C;Cheng G;Hu X;Liu C
解没食子链球菌巴氏杆菌是一种未被充分认识的病原体和人畜共患病病原体，可引起人类的机会性感染。尽管越来越多的人认识到该亚种是人类感染性疾病的原因，但关于其抗生素耐药性机制的信息有限。在这项研究中，我们的目的是确定潜在的大环内酯类高耐药的六个S的分子机制。解没食子酸亚种从2010-2013年中国几次自然暴发中收集的死亡雏鸭中分离的巴氏杆菌。所有菌株均表现出多重耐药，包括对大环内酯类抗生素的高度耐药（红霉素MIC ≥ 1024 mg/L，克拉霉素MIC ≥ 512 mg/L）。在这些分离株中未检测到编码流出物的mefA和mefE基因。特定分离株中23 S rRNA突变的存在并没有显著改变大环内酯类药物的MIC。在编码核糖体蛋白L4或L22的基因中没有发现核苷酸取代。ermB和ermT基因在所有分离株的基因组中被发现。这两个基因在一个强毒力分离物AL 101002中独立获得，并分别与Tn 916和IS 1216聚类。所有分离株中ermB和ermT的表达均为红霉素诱导型，并且在所有6种分离株中产生了可比的大环内酯类MIC。总之，ermB和ermT的诱导表达赋予这些S.解没食子酸亚种巴斯德菌分离株我们的研究结果揭示了新的大环内酯类耐药的特点，在S。解没食子酸亚种pasteurianus由ermB和ermT。
Streptococcus gallolyticus subsp. pasteurianus is an under-recognized pathogen and zoonotic agent causing opportunistic infections in humans. Despite increasing recognition of this subspecies as a cause for human infectious diseases, limited information is known about its antibiotic resistance mechanism. In this study, we aim to identify the molecular mechanism underlying the high macrolide resistance of six S. gallolyticus subsp. pasteurianus isolates from dead ducklings collected in several natural outbreaks in China during 2010–2013. All isolates exhibited multi-drug resistance including high macrolide resistance (MIC ≥ 1024 mg/L for erythromycin, and 512 mg/L for clarithromycin). Efflux-encoding mefA and mefE genes were not detectable in these isolates. The presence of 23S rRNA mutations in specific isolates did not significantly change macrolide MICs. No nucleotide substitutions were found in genes encoding ribosomal proteins L4 or L22. The ermB and ermT genes were found in the genomes of all isolates. These two genes were acquired independently in one highly virulent isolate AL101002, and clustered with Tn916 and IS1216, respectively. The expression of both ermB and ermT in all isolates was erythromycin inducible and yielded comparable macrolide MICs in all six isolates. Taken together, inducible expression of both ermB and ermT conferred high macrolide resistance in these S. gallolyticus subsp. pasterianus isolates. Our findings reveal new macrolide resistance features in S. gallolyticus subsp. pasteurianus by both ermB and ermT.